Not Applicable
Not Applicable
1. Field of Invention
This invention pertains to electrical bus. More particularly, this invention pertains to a captive splice system for connecting sections of electrical bus.
2. Description of the Related Art
Electrical buses are commonly used to connect various pieces of electrical equipment, including control centers, load centers, and switchgear. Buses typically include conductors for each phase and may include neutral and ground conductors. It is common for bus conductors to be made of a plurality of conducting bars. That is, each phase, neutral, or ground conductor has one or more conducting bars mounted parallel to each other.
Electrical bus is manufactured in sections, which have a specified length. During assembly, the various sections of electrical bus need to be connected, or spliced, to form an electrical circuit. It is well known in the art to splice bus bars by clamping splice plates or splice bars on either side of the bus bars. For bus sections with multiple bars, at the end where the splice is to be made, the bars have an air gap separating them that is equal to the thickness of the splice bars. Representative of improvements on the basic splice are the following patents: U.S. Pat. No. 4,174,143, issued to Hicks, et al., on Nov. 13, 1979, titled xe2x80x9cBus Duct Joint Employing Lightly-Loaded Multiple-Point Electrical Connector,xe2x80x9d discloses a single-bolt joint that is securely fastened to the end of one bus section and slidably engages the end of a second bus section with no further tightening of the single fastener. The Hicks patent discloses a bus joint that connects multiple phases and permits thermal expansion of the bus members.
U.S. Pat. No. 4,740,864, issued to Stanfield, et al., on Apr. 26, 1988, titled xe2x80x9cHorizontal Bus Bar Splice for Control Center,xe2x80x9d discloses a slidable splice plate assembly that sandwiches splice bars between the bus bars and has through-bolts to clamp the bars. The Stanfield patent discloses a splice plate assembly that includes an insulated slide plate with protruding tabs and nubs that serve to maintain the position of the splice bar. The sidable splice plate assembly connects bus bars of adjacent control center sections. When each section is shipped, the slidable splice plate assembly is fastened to the bus bars such that the edge of the assembly is flush with the end of the bus bars. After the sections are butted together, the assembly is slid along the bus bars until the joint between the bus bars of the adjacent sections is centered in the assembly, which is then bolted to the bus bars, forming an electrical splice.
According to one embodiment of the present invention, a captive bus bar splice assembly and a method for using same are provided. The captive splice assembly electrically and structurally links sections of electrical bus. The captive splice assembly is a self-contained splice assembly that minimizes the installation steps by having all the necessary components in a single assembly and holding captive the splice plates while positioning the assembly on the bus sections to be spliced.
The captive splice assembly includes a housing, which holds captive a set of splice bars. The housing has a set of captive nuts, which are engaged by a set of bolts which pass through the splice bars. After installation, the splice bars are interleaved with the bars of a pair of bus sections, and the bolts compress the splice bars and sections of bus, forming an electrical and structural connection between the pair of bus sections.
In one embodiment, the housing is fabricated of a non-magnetic metal. The housing has tangs or protrusions that engage slots in the splice bars and serve to prevent the splice bars from being ejected from the housing as the bus section is inserted into the captive splice assembly. The captive nuts are fixed to the back side of the housing. Another embodiment provides a housing fabricated of plastic material with the nuts held captive in either the plastic housing or by a splice bar which is adjacent to the back side of the housing.
One method of using the captive splice assembly is to assemble the splice assembly, slide the assembly fully onto a first bus section, butt a second bus section to the first, slide the assembly from the first bus section to the second such that the joint formed between the bus sections is substantially at the midpoint of the splice assembly, aligning the bolt holes in the bus sections and the splice assembly, and fastening the splice assembly to the bus sections by inserting and tightening bolts in the bolt holes.
Another method is to assemble the splice assembly, slide the assembly on a first bus section, align the assembly bolt holes with the bus section bolt holes, insert and tighten bolts in the bolt holes for the first bus section, and then insert a second bus section into the assembly, align the assembly bolt holes with the bus section bolt holes, insert and tighten bolts in the bolt holes for the second bus section.